Introduction to Advanced Cardiopulmonry Rehabilitation

1. Introduction to Advanced Cardiopulmonry Rehabilitation PED 596 Spring 2002

2. Review Physiological Responses to Exercise Exercise is Homeostatic Emergency

3. Acute = Accommodate • Immediate response to an “Exercise Emergency” • GOAL: Maintain homeostasis

4. Chronic = Adapt • Repeated exposures to “Exercise Emergencies” stimulate adaptive changes • Training Effects

5. Define “Exercise” • You should get more “exercise!” • Muscular activity (work) • Induces increased oxygen uptake • Increased cardiac output • Increased cellular energy metabolism • WORK CAPACITY and THE PHYSIOLOGICAL RESPONSE TO WORK

6. Bottom Line - Emergency #1: Exercise Demands: ATP supply and substrate delivery systems • ATP Supply: • Fuel Supply: Glucose, Fatty Acids • Oxygen Supply • Metabolic Machinery: Rate Regulating Enzymes • Delivery System: • Cardiopulmonary Systems

7. Bottom Line - Emergency #2: Exercise Demands: Better machinery • Work Output is an “external” product of exercise • Work Capacity is in part determined by Muscle strength • Muscle Strength: Function of cross-section and neurological efficiency

8. Adaptation: Improves the ability to respond to each “Homeostatic Emergency”

9. Specificity of Training: • Peripheral Adaptations: • Muscle Fiber: Protein synthesis, metabolic enzymes, mitochondrial density, glycogen, triglyceride and myoglobin stores • Angiogenesis • Central Adaptations: • Cardiovascular: Cardiac output, peripheral resistance, blood volume, RBC, ventilatory threshold, insulin sensitivity

10. Exercise Testing: Clinical

11. Clinical Indications for Exercise Testing: • Diagnosis: Reproduce symptoms • CP, SOB, Poor work tolerance • ECG changes? • Functional Testing: • Work Capacity, BP response to exercise, Exercise duration • Prognosis: • AHA, AACVPR, ACP: Risk Stratification, Duke’s 5-Year Mortality prognosis

12. Diagnosis: • Indications: • Confirm or rule out suspected myocardial ischemia • Mechanisms for syncope (LOC) • Suspected arrhythmias (palpitations with symptoms) during exercise

13. Functional Capacity: • Indications: • Assessing work capacity for return to work/leisure activites • Used in determining risk/prognostic stratification • Used in determining therapy choices • Exercise Prescription: Phase II Entrance requirements

14. Prognostic Benchmarks • <5 METs: poor prognosis especially under 65 years old • 10 METs: considered normal fitness: survival good – regardless of intervention • 13 METs: good prognosis even with CAD present

15. Less expensive Less space Quieter Less ECG artifact Easier BP’s Non-Weight dependent More flexibility in protocols More reproducible (not-patient dependent) More accurate work determinations Bike vs. Treadmill

16. Specificity of Testing: • Patient Preference / Experience • Diagnostic Protocols: • To Elicit Symptoms • Often quit at ~80% predicted HR Max

17. Critical Measurements: • Work Loads: MET calculations • ECG: Clean ST-Segment changes • BP: Accurate work SBP/DBP • RPP: MVO2 eliciting CP • Elicited Symptoms: CP, SOB, Syncope

18. Myocardial O2 demand (MVO2) depends on.. • Myocardial tension (pressure x volume) • Inotropic State (Measure?) • Chronotropic state (Measure?) • Myocardial mass

19. Indirect measure of MVO2 • Rate pressure product (a.k.a. double product, tension-time index) • Considers 2 of the MVO2 indices: • HR X SBP • Good estimate of oxygen use by the heart. • Used to determine angina threshold

20. 12-Lead ECG: Electrode Placement • RA/LA: • On Shoulders at distal ends of clavicles: (Not over large muscle masses) • RL/LL: • Base of Torso: Just medial to the iliac crests • Chest Leads: V1-V6 • Traditional precordial positioning

21. V1-V2: 4th intercostal space –R/L of sternum V4: 5th intercostal space – midclavicle line V3: Between V2 and V4 V5: At horizontal level of V4, anterior to axilla V6: Midaxillary at horizontal level of V4

22. Treadmill Protocols: • Treadmill Speed: Individualize • Increment Size: Age, condition • Larger incremental increases for younger, more fit patients • Smaller incremental increases for elderly, de-conditioned • Test Length: • Between 8-12 minutes

23. Estimating Work Capacity: Selecting Protocols • Healthy Men >40 years old • 75% have 12.5 MET capacity • 50% ~ 10 METs • Healthy Women >40 years old • 75% have 10 MET capacity • 50% ~8-9 METs • Choose a protocol that achieves the estimated MET capacity between 8-12 minutes

24. Commonly Used Clinical Protocols: • Naughton: 2.0 mph X 3.5% increases every 2 minutes • Max METs = 9 /16 minutes • Balke: 3.3 mph X 3% increases every 3 minutes • Max METs = 12 /18 minutes • McHenry: Similar to Balke but Stage I is 2.0 mph/3% grade

25. Measurements: HR, BP, ECG • Pre-Test: Supine and Exercise Position • Exercise: HR/BP in final minute of each stage – ECG every minute and whenever irregularities appear • Post-Test: Immediately post exercise and every 1-2 minutes until full recovery

26. Measurements: RPE, Symptoms • RPE: In the last minute of each stage • Symptoms: Note symptoms that occur: • Ask frequently, “How are you feeling?”

27. Rating Anginal Symptoms: • 1+: Light, barely noticeable • 2+: Moderate, bothersome • 3+: Severe, very uncomfortable • 4+: Most severe pain ever experienced

28. Post Exercise Period: • For Maximal Diagnostic Sensitivity: • No Cool Down • 10-sec ECG immediately • 6-8 minutes of supine monitoring* - record ECG every minute or after any irregularity *Unless patient is severely dyspneic – then sitting preferred

29. Testing Competencies: • Know Absolute and Relative indications for test termination: • 3+ to 4+ angina • Suspected MI • Drop in SBP with increased work • Serious arrhythmias • Signs of poor perfusion • Patient request

30. Exercise Test Endpoints: • Pre-determined HR achieved • Pre-determined Workload achieved • Patient c/o CP, SOB, leg pains, fatigue • ECG changes: • Significant ST changes • New Bundle branch or AV block • Increasing PVC frequency, VT or Fib

31. A Little Diagnostic Interaction HHMI Cardiology Lab

32. Cardiovascular Pharmacology Exercise Implications

33. Understanding the Role of Medications in Exercise: • What is the physiological response to exercise? • What is the mechanism of action of the drug? • Is there individual variability? • How are generalities best applied to exercise testing and prescription?

34. Cardiovascular Response to Exercise: Acute / Chronic • Changes in Autonomic Nervous System • SNS: Acute responses • PSNS: Resting status in trained persons • Cardiovascular Changes: • HR, BP, myocardial contractility, venous return, vascular resistance,

35. Therefore: • Any drug that acts on the autonomic nervous system, heart, blood vessels or kidneys may impact exercise

36. Diuretics: ACE Inhibitors Beta-blockers Ca++ Channel blockers Nitrates Anti-hypertensive Anti-hypertensive, CHF, Anti-hypertensive, tachycardias Anti-hypertensive, tachycardias Anti-anginal Drug Classifications: Mechanism: Use:

37. Diuretics: • Alter renal reabsorption or secretion of H2O and/or Na+ • Increase diuresis • Used for Hypertension and CHF • May cause electrolyte imbalances: especially K+

38. Commonly Used Diuretics: • Thiazide Diuretics: Diuril, (Lozol) • Loop Diuretics: Lasix, Bumex, Edecrin • K+ Sparing: Aldactone, Dyazide

39. Effects of Diuretics on Exercise: (See ACSM) • Very little effect except for decreased blood pressure • CAUTION: May cause PVC’s or false + ischemia signs with electrolyte imbalances

40. ACE Inhibitors: • Inhibits Renin-Angiotensin Aldosterone (RAA) System: • Renin is released from kidneys in response to hypotension/ Na+ • Renin increases levels of Angiotensin I (liver) • Angiotensin Converting Enzyme (ACE) converts Ang I to Angiotensin II (active)

41. What Does Angiotensin II Do? Vasoconstriction Blood Pressure Increase H2O and N+ Retention Stimulate release of ADH and Aldosterone Net Effect: Increase Blood Pressure

42. Therapeutic Uses of ACE Inhibitors: • Hypertension: Improved diuresis, vascular relaxation • CHF: The combined effect of diuresis, vascular relaxation reduces Pre/After-Loads on heart * Affects diuresis without direct action on kidneys – can be used in patients with impaired kidney function

43. Commonly Used ACE Inhibitors: • Captopril (Capoten): Used in mild to moderate hypertension • Vasotec, Lotensisn: Used in all hypertensions and CHF • Zestril, Prinivil: Once a day dosing

44. Effects of ACE Inhibitors on Exercise: • Little effect except to decrease blood pressure • May actually improve exercise capacity in patients with CHF

45. Beta-Blockers: • Beta-adrenoceptor antagonist: • Reduces SNS stimulation of Beta-receptors • Prolongs AV conduction ( HR) • Inhibit Phase 4 Depolarization • Decrease Contractility • Decreases MVO2 • Contraindicated: CHF*, asthma, diabetes

46. Therapeutic Uses Of Beta-Blockers: • Used for treating mild to moderate hypertension • Treating Angina • Reducing tachyarrhythmias

47. Commonly Used Beta-Blockers: • Inderal • Lopressor • Corgard • Blocadren • Tenormim • Lopressor

48. Effect of Beta-Blockers on Exercise: • Reduced resting and exercise HR/BP • Reduced ischemia • Exercise capacity equivocal: may decrease in patients without angina

49. Calcium Channel Blockers: • Block slow calcium channels in myocardial and vascular smooth muscle cells: • Reduce vasoconstriction • Decrease cardiac contractility • Decrease MVO2 • Can lead to AV-Block

50. Therapeutic Uses of Calcium Channel Blockers: • Treatment of Hypertension • Tachyarrhythmias • Cautious use in CHF